One of the best ways to learn in iRacing is by utilizing 'Ghost Racing.'

This allows users to enter a populated race or practice session, but as a spectator that is invisible to any of the regular drivers of the session. The other drivers will not see the ghost driver's name or car anywhere in the session. As a ghost you will also be unable to make contact with any cars in the session, you will simply drive through them. 

However, the ghost driver still experiences all of the other physics effects of being around other cars as if they were really in the session. The ghost driver will be able to draft behind real drivers and experience the same track condition changes. 

This is a great confidence-builder, and it's a great way to learn your way around a new track -- and even better, if you join a race session you can actually use this method to practice race starts.

Does It Impact My iRating and Safety Rating?

No! Driving as a ghost is similar to a test session, so there are no Safety Rating or iRating impacts from using this feature.

How to Enter a Session as a Ghost

Open the iRacing UI and go to "Go Racing" -> "Current Series", then choosing a a desired series that currently has a race running.
To join a Practice session as a spectator, select the chevron next to "Register" for the corresponding session, then select "Watch."

To join a Race session as a spectator, select the blue "Watch" button for the corresponding session.

Once you have registered and joined the session, you may start driving in ghost mode at any point by selecting "Test Drive."